Imidazole derivative

ABSTRACT

Novel imidazole derivatives and their acid adducts are disclosed. The imidazole derivatives are represented by formula: ##STR1## wherein R 1  represents an alkyl group, R 2  represents a hydrogen atom, an alkyl group which may have a substituent, or an aralkyl group which may have a substituent, provided that R 1  and R 2  are not both methyl groups at the same time. They have strong antimicrobial activity, especially against those fungi belonging to the genera Candida, Trichophyton, Microsporum, and Epidermorphyton, as well as against Gram-positive bacteria, and thus are useful as an antimicrobial agent.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to novel imidazole derivatives, and, more particularly, to novel imidazole derivatives having antimicrobial activities against Gram-positive bacteria, fungi, and the like.

2. Description of the Background

A number of imidazole derivatives having antimicrobial activities are conventionally known. Their antimicrobial activities, especially antifungal activities, are not necessarily satisfactory. Development of compounds having more effective activities are, therefore, required.

In view of this situation, the present inventors have undertaken extensive studies for the synthesis of various imidazole derivatives and for the detection of their pharmacological activities. As a result, the inventors have found that novel compounds represented by the following formula (I) exhibited strong antimicrobial activities, especially against Gram-positive bacteria, and fungi. This finding has led to the development and completion of this invention.

SUMMARY OF THE INVENTION

Accordingly, an object of this invention is to provide an imidazole derivative represented by formula (I): ##STR2## wherein R₁ represents an alkyl group, R₂ represents a hydrogen atom, an alkyl group which may have a substituent, or an aralkyl group which may have a substituent, provided that R₁ and R₂ are not both methyl groups at the same time; or an acid adduct thereof.

Other objects, features and advantages of the invention will hereinafter become more readily apparent from the following description.

DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS

Examples of alkyl groups represented by R₁ in formula (I) are linear, branched, or cyclic alkyl groups of a C₁₋₁₀ carbon atom content. Specific examples of especially preferable alkyl groups are methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, t-butyl, pentyl, hexyl, octyl and cyclopropyl groups, and the like.

Alkyl groups for R₂ of formula (I) include, for example, linear, branched, or cyclic alkyl groups of a C₁₋₁₆ carbon atom content. Given as examples of aralkyl groups for R₂ of formula (I) are phenylalkyl groups and naphthylalkyl groups. The substituted groups for the alkyl group include, for example, a halogen atom, a lower alkoxy group, a lower alkanoyl group, a cyano group, and the like. When R₂ is an aralkyl group, the substituted groups for the aryl group of the aralkyl portion may be a halogen atom, a lower alkyl group, a lower alkoxy group, a lower alkanoyl group, a cyano group, and the like.

Among the compounds of formula (I) those having a hydrogen atom for R₂, i.e., Compound (Ia), can be prepared according to the following reaction formula, i.e., by reacting 1-(2-hydroxyphenacyl)imidazole (II) and a Grignard reagent (III). Compounds of formula (I) in which the R₂ is an alkyl or aralkyl group which may have a substituent, i.e., Compound (Ib), can be prepared by reacting Compound (Ia) with an alkylation or aralkylation reagent (IV) according to the following reaction formula: ##STR3## wherein R₁ has the meaning defined previously, X₁ and X₂ represent halogen atoms, and R₂, represents an alkyl or aralkyl group which may have a substituent.

The reaction for preparing Compound (Ia) is performed by using 1 to 5 moles of compound (III) for 1 mole of compound (II) in a solvent such as ether, tetrahydrofuran, or the like. The reaction is carried out at a temperature between 0° C. and the boiling point of the reaction mixture for 1 to several hours. After completion of the reaction, the surplus amount of compound (III) and addition salt produced in the reaction are decomposed using an aqueous solution of ammonium chloride, or the like. The mixture is extracted with a solvent such as chloroform or the like and, after evaporation of the solvent, pure Compound (Ia) can be obtained by silica gel chromatography or the like.

The reaction for the preparation of Compound (Ib) may be carried out using 1 to 2 moles of compound (IV) per one mole of Compound (Ia) in the presence of an alkali from room temperature to the boiling point of the solvent used, for 1 hour to 50 hours. Solvents which can be used include dimethylformamide, dimethylsulfoxide, acetone, ethanol, methanol, chloroform, methylene chloride, and the like. Given as examples of alkali which can be used in the reaction are sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, and the like. After completion of the reaction, the reaction mixture is charged into water, and this mixture is extracted with a solvent such as ether or the like. After evaporation of the solvent, pure Compound (Ib) can be obtained by silica gel chromatography or the like.

The compound of formula (I) of this invention can be converted into an acid adduct through any conventional method. Given as examples of such acid adducts are those of pharmaceutically or medicinally permissible acids, including inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, hydrobromic acid and the like; and organic acids such as acetic acid, oxalic acid, fumaric acid, maleic acid, citric acid, malic acid, succinic acid, and the like.

Hereinafter are presented experimental examples to further illustrate the effectiveness of the invention. These examples are given for illustration of the invention and are not intended to be limiting thereof.

EXPERIMENTAL EXAMPLES

Antimicrobial activities of certain representative compounds of this invention, which had been obtained in the above-described manner, were investigated. Results are summarized in Table 1, in which the compound numbers correspond to those to be given in Examples which will be described herein.

                  TABLE 1                                                          ______________________________________                                                         Compound tested MIC (μg/ml)                                 Microorganism tested                                                                             Compound 8  Compound 59                                      ______________________________________                                         Bacillus subtilis ATCC 6633                                                                      3.12        6.25                                             Staphylococcus aureus FDA 209P                                                                   3.12        6.25                                             Staphylococcus aureus Terajima                                                                   3.12        6.25                                             Staphylococcus aureus Smith                                                                      3.12        6.25                                             Staphylococcus epidermidis                                                                       0.39        1.56                                             ATCC 12228                                                                     Sarcina lutea ATCC 9341                                                                          0.20        0.05                                             Streptococcus faecalis IFO 12964                                                                 6.25        6.25                                             Micrococcus lysodeikticus                                                                        1.56        1.56                                             IFO 3333                                                                       Candida albicans NHL 4019                                                                        12.5        12.5                                             Candida albicans Yu-1200                                                                         12.5        25.0                                             Saccharomyces cerevisiae                                                                         0.025       12.5                                             ATCC 9763                                                                      Saccharomyces ruxii 6507                                                                         0.39        0.78                                             Aspergillus niger ATCC 9642                                                                      0.025       0.10                                             Penicillium chrysogenum                                                                          3.12        6.25                                             ATCC 6010                                                                      Trichophyton mentagrophytes                                                                      0.006       <0.006                                           QM 248                                                                         Trichophyton mentagrophytes                                                                      <0.006      <0.006                                           IFO 5812                                                                       Trichophyton tonsurans IFO 5928                                                                  <0.006      <0.006                                           Trichophyton rubrum NHL J                                                                        <0.006      <0.006                                           Microsporum gypseum IFO 8231                                                                     0.006       <0.006                                           Microsporum audounii IFO 6074                                                                    <0.006      <0.006                                           Microsporum cookei IFO 8303                                                                      0.012       0.10                                             Epidermophyton floccosum                                                                         0.10        0.20                                             IFO 9045                                                                       Aspergillus oryzae IMF 4014                                                                      <0.006      <0.006                                           Cladosporium fulvum IAM 5006                                                                     0.78        1.56                                             Fusarium moniliforme IAM 5062                                                                    3.12        6.25                                             Helminthosporium sesamum                                                                         <0.006      <0.006                                           IAM 5012                                                                       Pyricularia oryzae IAM 5016                                                                      <0.006      <0.006                                           Debaryomyces kloeckeri IFO 0015                                                                  3.12        12.5                                             Gibberella fujikuroi IAM 8046                                                                    0.78        1.56                                             ______________________________________                                    

Compound (I) prepared as fully described above has strong antimicrobial activity, especially against those fungi belonging to the genera Candida, Trichophyton, Microsporum, Epidermorphyton, and the like, as well as Gram-positive bacteria, and thus is useful as a antimicrobial agent.

Other features of the invention will become apparent in the course of the following description of the exemplary embodiments which are given for illustration of the invention and are not intended to be limiting thereof.

EXAMPLES Example 1 Preparation of 1-[2-hydroxy-2-(2-hydroxyphenyl)pentyl]imidazole (Compound 18)

To a tetrahydrofuran solution of Grignard reagent prepared from 73 mg of magnesium and 369 mg of n-propyl bromide, 202 mg of 1-(2-hydroxyphenacyl) imidazole (II) was added dropwise under ice-cooled conditions while stirring, and the mixture was refluxed for 2 hours. After ice-cooling, an aqueous solution of ammonium chloride was added to the mixture to decompose the surplus amount of the Grignard reagent and addition salts produced in the reaction. Extraction with chloroform was performed on this mixture and the chloroform layer was washed with water, followed by drying over anhydrous magnesium sulfate. The extract thus obtained was purified by means of silica gel column chromatography (eluent: chloroform) to produce 70 mg of the title compound at a yield of 29%.

Example 2 Preparation of 1-[2-hydroxy-2-(2-ethoxyphenyl)pentyl]imidazole (Compound 20)

34 mg of 1-[2-hydroxy-2-(2-hydroxyphenyl)pentyl]imidazole (Compound 18) was dissolved into 10 ml of dimethylformamide, and 33 mg of ethyl iodide and 10 mg of sodium hydroxide was added to this solution. The mixture was stirred at room temperature for 20 hours. The reaction mixture, after being charged into ice water, was subjected to extraction with ether. The ether layer was then washed with water, followed by drying over anhydrous magnesium sulfate. The extract thus obtained was purified by means of silica gel column chromatography (eluent: methylene chloride) to produce 22 mg of the title compound at a yield of 58%.

Example 3

Reactions were carried out in the same manner as in Examples 1 and 2 to synthesize the compounds listed in Table 2. The compounds produced in Examples 1 and 2 are also listed in the table.

    TABLE 2       Compound      No. R.sub.1 R.sub.2 Appearance IR(νcm.sup.-1) NMR(CDC1.      sub.3) δ(ppm)        1 CH.sub.3 H White crystals 3350, 2350, 1.53 (s, 3H), 4.10 (d, 1H),      4.30 (d, 1H), 6.6-7.4 (m, 7H),    m.p.163-165° C. 1510, 1230 8.75      (s, 2H) 2 CH.sub.3 C.sub.2 H.sub.5 Oily substance 3200, 3000, 1.47 (t,      3H), 1.53 (s, 3H), 4.06 (q, 2H), 4.27 (s, 2H),     1450, 1230 4.63 (s,      1H), 6.6-7.5 (m, 7H) 3 CH.sub.3 C.sub.3 H.sub.7 Oily substance 3150,      2960, 1.06 (t, 3H), 1.53 (s, 3H), 1.7-2.1 (m, 2H), 3.98 (t, 2H),      1440, 1220 4.27 (s, 2H), 4.36 (s, 1H), 6.6-7.4 (m, 7H) 4 CH.sub.3      C.sub.4 H.sub.9 Oily substance 3150, 2940, 0.7-1.1 (t-like, 3H), 1.1-2.1      (m, 4H), 1.54 (s, 3H),     1445, 1225 4.06 (t, 2H), 3.9-4.2 (m, 1H),      4.31 (s, 2H), 6.6-7.4 (m, 7H) 5 CH.sub.3 C.sub.5 H.sub.11 Oily substance      3150, 2950, 0.7-1.0 (t-like, 3H), 1.1-2.1 (m, 6H), 1.47 (s, 3H),      1445, 1230 3.97 (t, 2H), 4.24 (s, 2H), 4.35 (s, 1H), 6.6-7.4 (m, 7H) 6      CH.sub.3 C.sub.6 H.sub.13 Oily substance 3150, 2950, 0.7-1.1 (t-like,      3H), 1.1-2.3 (m, 8H), 1.52 (s, 3H),     1450, 1230 4.00 (t, 2H), 4.28      (s, 2H), 4.90 (s, 1H), 6.6-7.4 (m, 7H) 7 CH.sub.3 C.sub.7 H.sub.15 Oily      substance 3150, 2950, 0.7-1.1 (t-like, 3H), 1.1-2.1 (m, 10H), 1.53 (s,      3H),     1445, 1235 4.00 (t, 2H), 4.30 (s, 2H), 5.30 (s, 1H), 6.6-7.5      (m, 7H) 8 CH.sub.3 C.sub.8 H.sub.17 Oily substance 3150, 2950, 0.6-1.0      (t-like, 3H), 1.0-2.0 (m, 12H), 1.53 (s, 3H),     1450, 1235 4.02 (t,      2H), 4.31 (s, 2H), 4.75 (s, 1H), 6.5-7.5 (m, 7H) 9 C.sub.2 H.sub.5 H      White crystals 3140, 2980, 0.85 (t, 3H), 1.4-2.3 (m, 2H), 4.16 (d, 1H),      4.18 (d, 1H),    m.p.155-157° C. 1450, 1240 6.6-7.4 (m, 7H),      8.6-9.0 (m, 2H) 10 C.sub.2 H.sub.5 CH.sub.3 White crystals 3200, 2950,      0.74 (t, 3H), 1.3-2.4 (m, 2H), 3.77 (s, 3H), 3.97 (s, 1H),    m.p.      94-96° C. 1445, 1240 4.20 (d, 1H), 4.27 (d, 1H), 6.5-7.4 (m, 7H)      11 C.sub.2 H.sub.5 C.sub.2 H.sub.5 Oily substance 3180, 3000, 0.74 (t,      3H), 1.43 (t, 3H), 1.6-2.5 (m, 2H), 4.06 (q, 2H),     1450, 1240 4.26      (d, 1H), 4.33 (s, 1H), 4.40 (d, 1H), 6.6-7.5 (m, 7H) 12 C.sub.2 H.sub.5      C.sub.3 H.sub.7 Oily substance 3180, 2980 0.73 (t, 3H), 1.04 (t, 3H),      1.3-2.6 (m, 4H), 3.97 (t, 2H),     1450, 1230 4.16 (s, 1H), 4.28 (d,      1H), 4.33 (d, 1H), 6.6-7.5 (m, 7H) 13 C.sub.2 H.sub.5 C.sub.4 H.sub.9      Oily substance 3180, 2980, 0.72 (t, 3H), 0.97 (t, 3H), 1.1-2.6 (m, 6H),      4.00 (t, 2H),     1450, 1240 4.27 (d, 1H), 4.36 (d, 1H), 4.59 (s, 1H),      6.6-7.5 (m, 7H) 14 C.sub.2 H.sub.5 C.sub.5 H.sub.11 Oily substance 3160,      2950, 0.74 (t, 3H), 0.93 (t, 3H), 1.1-2.6 (m, 6H), 3.99 (t, 2H),      1450, 1230 4.27 (d, 1H), 4.38 (d, 1H), 4.47 (s, 1H), 6.6-7.5 (m, 7H) 15      C.sub.2 H.sub.5 C.sub.6 H.sub.13 Oily substance 3190, 2960, 0.77 (t, 3H)      0.90 (t, 3H), 1.1-2.6 (m, 10H), 3.97 (t, 2H),     1455, 1235 4.23 (s,      1H), 4.29 (d, 1H), 4.35 (d, 1H), 6.6-7.5 (m, 7H) 16 C.sub.2 H.sub.5      C.sub.7 H.sub.15 Oily substance 3180, 2950, 0.73 (t, 3H), 0.7-1.1      (t-like, 3H), 1.1-2.6 (m, 12H), 4.00 (t, 2H),     1455, 1235 4.28 (d,      1H), 4.40 (d, 1H), 4.77 (s, 1H), 6.6-7.6 (m, 7H) 17 C.sub.2 H.sub.5      C.sub.8 H.sub.17 Oily substance 3180, 2960, 0.73 (t, 3H), 0.7-1.0      (t-like, 3H), 1.0-2.5 (m, 14H), 4.00 (t, 2H),     1455, 1235 4.28      (d,1H), 4.37 (d, 1H), 4.67 (s, 1H), 6.5-7.5 (m, 7H) 18 C.sub.3 H.sub.7 H      Oily substance 3140, 2980, 0.7-1.1 (t-like, 3H), 1.1-2.3 (m, 4H), 4.06      (d, 1H),     1450, 1240 4.23 (d, 1H), 6.6-7.4 (m, 7H), 8.0-8.4 (m, 2H)      19 C.sub.3 H.sub.7 CH.sub.3 Oily substance 3200, 2980, 0.7-1.1 (t-like,      3H), 1.1-2.5 (m, 4H), 3.82 (s, 3H), 3.83 (s, 1H),     1440, 1240 4.20      (d, 1H), 4.37 (d, 1H), 6.6-7.5 (m, 7H) 20 C.sub.3 H.sub.7 C.sub.2      H.sub.5 Oily substance 3160, 2980, 0.7-1.0 (t-like, 3H), 1.0-1.8 (m,      4H), 1.42 (t, 3H), 4.10 (q, 2H),     1450, 1235 4.28 (d, 1H), 3.8-4.2      (m, 1H), 4.46 (d, 1H), 6.6-7.4 (m, 7H) 21 C.sub.3 H.sub.7 C.sub.3      H.sub.7 Oily substance 3160, 2980, 0.7-1.0 (t-like, 3H), 1.05 (t, 3H),      1.2-2.5 (m, 6H), 3.5-3.7     1455, 1235 (m, 1H), 3.97 (t, 2H), 4.19 (d,      1H), 4.40 (d, 1H), 6.6-7.6 (m, 7H) 22 C.sub.3 H.sub.7 C.sub.4 H.sub.9      Oily substance 3160, 2990, 0.7-1.0 (t-like, 3H), 1.00 (t, 3H), 1.1-2.3      (m, 8H), 3.8-4.2     1455, 1235 (m, 1H), 4.07 (t, 2H), 4.27 (d, 1H),      4.42 (d, 1H), 6.6-7.4 (m, 7H) 23 C.sub.3 H.sub.7 C.sub.5 H.sub.11 Oily      substance 3180, 2980, 0.7-1.1 (t-like, 6H), 1.1-2.5 (m, 10H), 4.01 (t,      2H), 4.20     1455, 1235 (d, 1H), 4.34 (s, 1H), 4.47 (d, 1H), 6.6-7.5      (m, 7H) 24 C.sub.3 H.sub.7 C.sub.6 H.sub.13 Oily substance 3180, 2990,      0.6-1.1 (t-like, 6H), 1.1-2.5 (m, 12H), 3.99 (t, 2H), 4.20     1455,      1235 (d, 1H), 4.43 (d, 1H), 4.74 (s, 1H), 6.6-7.5 (m, 7H) 25 C.sub.3      H.sub.7 C.sub.7 H.sub.15 Oily substance 3170, 2960, 0.6-1.0 (t-like,      6H), 1.0-2.3 (m, 14H), 4.01 (t, 2H), 4.31     1455, 1235 (s, 1H), 4.33      (d, 1H), 4.38 (d, 1H), 6.6-7.6 (m, 7H) 26 C.sub.3 H.sub.7 C.sub.8      H.sub.17 Oily substance 3170, 2950, 0.6-1.0 (t-like, 6H), 1.0-2.3 (m      16H), 4.00 (t, 2H), 4.06     1455, 1235 (s, 1H), 4.24 (d, 1H), 4.33 (d,      1H), 6.5-7.5 (m, 7H) 27 C.sub.4 H.sub.9 H Oily substance 3200, 2970,      0.7-1.1 (t-like, 3H), 1.1-2.2 (m, 6H), 3.5-3.8 (m, 2H), 4.15     1455,      1240 (d, 1H), 4.22 (d, 1H), 6.4-7.3 (m, 7H) 28 C.sub.4 H.sub.9 CH.sub.3      Oily substance 3170, 2980, 0.77 (t, 3H), 0.9-2.4 (m, 6H), 3.80 (s, 3H),      3.9-4.2 (m, 1H),     1440, 1240 4.18 (d, 1H), 4.25 (d, 1H), 6.5-7.4 (m,      7H) 29 C.sub.4 H.sub.9 C.sub.2 H.sub.5 Oily substance 3180, 2980, 0.80      (t, 3H), 1.0-2.4 (m, 6H), 1.44 (t, 3H), 4.06 (q, 2H),     1450, 1235      4.10 (s, 1H), 4.25 (d, 1H), 4.33 (d, 1H), 6.5-7.4 (m, 7H) 30 C.sub.4      H.sub.9 C.sub.3 H.sub.7 Oily substance 3180, 2980, 0.80 (t, 3H), 1.09      (t, 3H), 1.0-2.4 (m, 8H), 3.97 (t, 2H),     1450, 1235 4.28 (d, 1H),      4.36 (s, 1H), 4.38 (d, 1H), 6.5-7.5 (m, 7H) 31 C.sub.4 H.sub.9 C.sub.4      H.sub.9 Oily substance 3170, 2970, 0.80 (t, 3H), 1.00 (t, 3H), 1.1-2.6      (m, 10H), 4.01 (t, 2H),     1450, 1235 4.29 (d, 1H), 4.38 (d, 1H), 4.80      (s, 1H), 6.5-7.5 (m, 7H) 32 C.sub.4 H.sub.9 C.sub.5 H.sub.11 Oily      substance 3180, 2980, 0.87 (t, 3H), 0.92 (t, 3H), 1.0-2.5 (m, 12H), 4.00      (t, 2H),     1455, 1235 4.28 (d, 1H), 4.38 (d, 1H), 4.84 (s, 1H), 6.6-      7.6 (m, 7H) 33 C.sub.4 H.sub.9 C.sub.6 H.sub.13 Oily substance 3170,      2950, 0.7-1.1 (t-like, 6H), 1.1-2.5 (m, 14H), 4.02 (t, 2H), 4.30      1450, 1235 (d, 1H), 4.39 (d, 1H), 4.47 (s, 1H), 6.6-7.6 (m, 7H) 34      C.sub.4 H.sub.9 C.sub.7 H.sub.15 Oily substance 3170, 2950, 0.6-1.0      (t-like, 6H), 1.0-2.5 (m, 16H), 4.00 (t, 2H), 4.00     1455, 1235 (s,      1H), 4.25 (d, 1H), 4.34 (d, 1H), 6.5-7.5 (m, 7H) 35 C.sub.4 H.sub.9      C.sub.8 H.sub.17 Oily substance 3170, 2950, 0.6-1.1 (t-like, 6H),      1.1-2.4 (m, 18H), 3.80 (s, 1H), 4.00     1450, 1235 (t, 2H), 4.24 (d,      1H), 4.35 (d, 1H), 6.6-7.5 (m, 7H) 36 C.sub.5 H.sub.11 H White crystals      3190, 2960, 0.7-1.0 (t-like, 3H), 1.0-2.5 (m, 8H), 4.27 (d, 1H), 4.46      m.p. 148-150° C. 1450, 1235 (d, 1H), 6.6-7.6 (m, 9H) 37 C.sub.5      H.sub.11 C.sub.2 H.sub.5 Oily substance 3200, 2990, 0.6-1.0 (t-like,      3H), 1.0-2.5 (m, 8H), 1.43 (t, 3H), 3.86 (s, 1H),     1455, 1245 4.05      (q, 2H), 4.25 (d, 1H), 4.34 (d, 1H), 6.6-7.5 (m, 7H) 38 C.sub.5 H.sub.11      C.sub.3 H.sub.7 Oily substance 3200, 2980, 0.7-1.0 (t-like, 6H), 1.0-2.5      (m, 10H), 3.96 (t, 2H), 4.21     1450, 1235 (s, 1H), 4.27 (d, 1H), 4.34      (d, 1H), 6.6-7.5 (m, 7H) 39 C.sub.5 H.sub.11 C.sub.4 H.sub.9 White      crystals 3150, 2940, 0.6-1.0 (t-like, 6H), 1.0-2.5 (m, 12H), 4.01 (t,      2H), 4.28    m.p. 74-76° C. 1440, 1225 (d, 1H), 4.38 (d, 1H),      4.83 (s, 1H), 6.5-7.5 (m, 7H) 40 C.sub.5 H.sub.11 C.sub.5 H.sub.11 White      crystals 3160, 2940, 0.6-1.0 (t-like, 6H), 1.0-2.5 (m, 14H), 4.02 (t,      2H), 4.31    m.p. 74-76° C. 1450, 1240 (d, 1H), 4.40 (d, 1H),      4.83 (s, 1H), 6.5-7.5 (m, 7H) 41 C.sub.5 H.sub.11 C.sub.6 H.sub.13 Oily      substance 3200, 2980, 0.6-1.0 (t-like, 6H), 1.0-2.5 (m, 16H), 4.02 (t,      2H), 4.27     1455, 1240 (d, 1H), 4.38 (d, 1H), 4.66 (s, 1H), 6.4-7.5      (m, 7H) 42 C.sub.5 H.sub. 11 C.sub.7 H.sub.15 Oily substance 3200, 2960,      0.6-1.1 (t-like, 6H), 1.1-2.5 (m, 18H), 4.01 (t, 2H), 4.28     1455,      1240 (d, 1H), 4.38 (d, 1H), 4.67 (s, 1H), 6.5-7.5 (m, 7H) 43 C.sub.5      H.sub.11 C.sub.8 H.sub.17 Oily substance 3200, 2960, 0.5-1.0 (t-like,      6H), 1.0-2.5 (m, 20H), 4.00 (t, 2H), 4.28     1455, 1235 (d, 1H), 4.38      (d, 1H), 4.65 (s, 1H), 6.4-7.5 (m, 7H)  44 C.sub.3       H.sub.7      ##STR4##       Oily substance 3200, 2960,1455, 1230 0.6-1.0 (t-like, 3H), 1.0-2.5 (m,      4H), 3.46 (brs, 1H), 4.20(d, 1H), 4.30 (d, 1H), 5.09 (s, 2H), 6.5-7.6      (m, 7H), 7.40 (s, 5H)  45 C.sub.3       H.sub.7      ##STR5##       White crystalsm.p. 145-146° C. 3200, 2980,1490, 1235 0.6-1.0      (t-like, 3H), 1.0-2.5 (m, 4H), 3.85 (brs, 1H), 4.23(d, 1H), 4.33 (d,      1H), 5.04 (s, 2H), 6.5-7.6 (m, 11H)       46 C.sub.3 H.sub.7      ##STR6##       Oily substance 3190, 2990,1500, 1230 0.6-1.0 (t-like, 3H), 1.0-2.5 (m,      4H), 4.18 (d, 1H), 4.32 (brs, 1H),4.35 (d, 1H), 5.03 (s, 2H), 6.5-8.0      (m, 7H), 7.36 (s, 4H)  47 C.sub.3       H.sub.7      ##STR7##       White crystalsm.p. 137-138° C. 3130, 2970,1490, 1235 0.6-1.0      (t-like, 3H), 1.0-2.5 (m, 4H), 3.56 (brs, 1H), 4.20(d, 1H), 4.36 (d,      1H), 5.13 (s, 2H), 6.5-7.5 (m, 10H)  48 C.sub.3       H.sub.7      ##STR8##       White crystalsm.p. 127-128° C. 3130, 2970,1510, 1225 0.6-1.0      (t-like, 3H), 1.0-2.5 (m, 4H), 3.73 (s, 1H), 3.73 (s, 1H), 4.20 (d,      1H),4.30 (d, 1H), 5.02 (s, 2H), 6.5-7.7 (m, 11H)  49 C.sub.3 H.sub.7       ##STR9##       Oily substance 3150, 2990,1510, 1230 0.6-1.0 (t-like, 3H), 1.0-2.4 (m,      4H), 3.64 (s, 1H), 4.20 (d, 1H),4.30 (d, 1H), 5.08 (s, 2H), 6.4-7.6 (m,      10H)  50 C.sub.3       H.sub.7      ##STR10##       Oily substance 3100, 2940,1445, 1225 0.6-1.0 (t-like, 3H), 1.0-2.1 (m,      4H), 2.7-3.0 (m, 1H), 3.14(t, 2H), 4.16 (t, 2H), 4.0-4.4 (m, 2H),      6.5-7.6 (m, 12H)  51 C.sub.3       H.sub.7      ##STR11##       Oily substance 3300, 2960,1495, 1240 0.6-1.0 (t-like, 3H), 1.0-2.1 (m,      4H), 2.7-3.0 (m, 1H), 3.10(t, 2H), 4.18 (t, 2H), 4.0-4.4 (m, 2H),      6.5-7.6 (m, 11H)  52 C.sub.3       H.sub.7      ##STR12##       Oily substance 3130, 2980,1495, 1230 0.6-1.0 (t-like, 3H), 1.0-2.2 (m,      4H), 3.0-3.2 (m, 1H), 3.18(t, 2H), 4.20 (t, 2H), 4.0-4.4 (m, 2H),      6.5-7.6 (m, 11H)  53 C.sub.3       H.sub.7      ##STR13##       Oily substance 3150, 2960,1510, 1230 0.6-1.0 (t-like, 3H), 1.0-2.2 (m,      4H), 2.7-3.0 (m, 1H), 3.12(t, 2H), 4.20 (t, 2H), 4.0-4.4 (m, 2H),      6.5-7.6 (m, 11H)  54 C.sub.3 H.sub.7 CH(CH.sub.3).sub.2 White crystals      3160, 2990, 0.6-1.0 (t-like, 3H), 1.0-2.5 (m, 4H), 1.33 (d, 3H), 1.43      (d, 3H), 3.49    m.p. 126-128° C. 1490, 1230 (s, 1H), 4.23 (d,      1H), 4.34 (d, 1H), 4.34 (d, 1H), 4.4-4.9 (m, 1H), 6.5 -7.4 (m, 7H) 55      C.sub.3 H.sub.7 CH.sub.2 CH(CH.sub.3).sub.2 Oily substance 3180, 2990,      0.6-1.0 (t-like, 3H), 1.0-2.5 (m, 5H), 1.08 (d, 6H), 3.79 (d, 2H),      1475, 1235 4.10 (s, 1H), 4.27 (d, 1H), 4.37 (d, 1H), 6.5-7.5 (m, 7H) 56      C.sub.3 H.sub.7 (CH.sub.2).sub.2 CH(CH.sub.3).sub.2 Oily substance 3200,      2980, 0.6-1.0 (t-like, 3H), 0.99 (d, 6H), 1.0-2.3 (m, 7H), 3.70 (s, 1H),          1455, 1235 4.03 (t, 2H), 4.25 (d, 1H), 4.35 (d, 1H), 6.5 -7.4 (m,      7H) 57 C.sub.3 H.sub.7 CH.sub.2 CH.sub.2 Cl White crystals 3140, 2970,      0.6-1.0 (t-like, 3H), 1.0-2.6 (m, 4H), 3.8-4.1 (m, 2H), 4.2-4.5    m.p.      123-125° C. 1445, 1235 (m, 3H), 4.30 (d, 1H), 4.43 (d, 1H),      6.7-7.6 (m, 7H) 58 C.sub.3 H.sub.7 CH.sub.2 CH.sub.2 F Oily substance      3180, 2980, 0.6-1.0 (t-like, 3H), 1.0-2.6 (m, 4H), 4.05 (s, 1H), 3.9-4.5      (m, 2H),     1445, 1235 4.33 (d, 1H), 4.39 (d, 1H), 4.67 (dt, 2H),      6.6-7.6 (m, 7H) 59 CH.sub.3 C.sub.9 H.sub.19 Oily substance 3150, 2940,      0.7-1.1 (t-like, 3H), 1.1-2.3 (m, 14H), 1.53 (s, 3H), 4.02 (t, 2H),      1450, 1230 4.30 (s, 2H), 4.66 (s, 1H), 6.6-7.5 (m, 7H) 60 CH.sub.3      C.sub.10 H.sub.21 Oily substance 3150, 2920, 0.7-1.1 (t-like, 3H),      1.1-2.5 (m, 16H), 1.55 (s, 3H), 4.03 (t, 2H),     1450, 1230 4.31 (s,      2H), 4.45 (s, 1H), 6.6-7.5 (m, 7H) 61 CH.sub.3 C.sub.11 H.sub.23 Oily      substance 3160, 2920, 0.7-1.1 (t-like, 3H), 1.1-2.5 (m, 18H), 1.54 (s,      3H), 4.02 (t, 2H),     1440, 1230 4.03 (s, 1H), 4.28 (s, 2H), 6.6-7.5      (m, 7H)  62 C.sub.3       H.sub.7      ##STR14##       Oily substance 3160, 2950,1450, 1230 0.6-1.0 (t-like, 3H), 1.0-2.5 (m,      4H), 4.26 (d, 1H), 4.33 (d, 1H),4.5-4.7 (brs, 1H), 5.14 (s, 2H), 6.5-7.6      (m, 11H)  63 C.sub.3       H.sub.7      ##STR15##       White crystalsm.p. 143-144° C. 3150, 2950,1450, 1230 0.6-1.0      (t-like, 3H), 1.0-2.5 (m, 4H), 4.23 (d, 1H), 4.33 (d, 1H),4.2-4.3 (brs,      1H), 5.09 (s, 2H), 6.5-7.6 (m, 11H)  64 C.sub.3       H.sub.7      ##STR16##       Oily substance 3150, 2950,1450, 1230 0.7-3.0 (m, 11H), 3.8-4.3 (m, 2H),      4.2-4.6 (m, 2H),6.5-7.7 (m, 7H)  65 C.sub.3       H.sub.7      ##STR17##       Oily substance 3150, 2950,1450, 1230 0.3-2.6 (m, 12H), 3.82 (d, 2H),      4.27 (d, 1H), 4.41 (d, 1H), 4.2-4.5(brs, 1H), 6.5-7.5 (m, 7H)  66      C.sub.3       H.sub.7      ##STR18##       Oily substance 3150, 2950,1450, 1230 0.2-2.7 (m, 15H), 3.8-4.2 (m, 1H),      4.29 (d, 1H), 4.40 (d, 1H),4.9-5.3 (m, 1H), 6.6-7.7 (m, 7H)  67 C.sub.3      H.sub.7 (CH.sub.2).sub.3 CH(CH.sub.3).sub.2 Oily substance 3150, 2950,      0.6-1.1 (t-like, 3H), 0.95 (d, 6H), 1.1-2.5 (m, 9H), 3.4-3.7 (brs, 1H),         1450, 1230 4.02 (t, 2H), 4.27 (d, 1H), 4.39 (d, 1H), 6.6-7.5 (m, 7H)      68 C.sub.3       H.sub.7      ##STR19##       White crystalsm.p. 67-68° C. 3150, 2960,1510, 1220 0.7-1.1      (t-like, 3H), 1.1-2.3 (m, 4H), 2.6-3.0 (brs, 1H), 4.17(d, 1H), 4.30 (d,      1H), 5.1-5.4 (brs, 2H), 6.5-7.5 (m, 7H)  69 C.sub.3       H.sub.7      ##STR20##       Oily substance 3150, 2950,1450, 1230 0.6-1.0 (t-like, 3H), 1.0-2.5 (m,      4H), 2.16 (t, 2H),2.7-3.0 (m, 2H), 2.9-3.2 (m, 1H), 4.02 (t, 2H), 4.28      (d, 1H),4.39 (d, 1H), 6.7-7.5 (m, 7H), 7.24 (s, 5H)       70 CH(CH.sub.3).sub.2C.sub.3 H.sub.7 White crystals 3140, 2960, 0.71      (d, 3H), 1.09 (d, 3H), 0.8-1.3 (t-like, 3H), 1.5-2.1 (m, 2H),    m.p.      89-91° C. 1440, 1220 2.3-2.8 (m, 1H), 3.4-3.7 (brs, 1H), 3.7-4.1      (t-like, 2H), 4.23      (d, 1H), 4.60 (d, 1H), 6.5-7.5 (m, 7H) 71      CH(CH.sub.3).sub.2 C.sub.4 H.sub.9 White crystals 3150, 2970, 0.70 (d,      3H), 1.06 (d, 3H), 0.7-1.2 (t-like, 3H), 1.2-2.1 (m, 4H),    m.p.      119-121° C. 1440, 1240 2.2-2.9 (m, 1H), 3.7-4.1 (t-like, 2H),      4.1-4.3 (brs, 1H), 4.25      (d, 1H), 4.61 (d, 1H), 6.5-7.4 (m, 7H) 72      CH(CH.sub.3).sub.2 C.sub.5 H.sub.11 White crystals 3150, 2970, 0.73 (d,      3H), 1.09 (d, 3H), 0.7-1.1 (t-like, 3H), 1.1-2.2 (m, 6H),    m.p.      122-123° C. 1440, 1230 2.3-3.0 (m, 1H), 3.6-4.1 (m, 3H), 4.27 (d,      1H), 4.61 (d, 1H),      6.5-7.4 (m, 7H) 73 CH(CH.sub.3).sub.2 C.sub.6      H.sub.13 White crystals 3150, 2960, 0.71 (d, 3H), 1.09 (d, 3H), 0.7-1.1      (t-like, 3H), 1.1-2.3 (m, 8H),    m.p. 103-105° C. 1440, 1220      2.3-3.0 (m, 1H), 3.5-3.8 (brs, 1H), 3.7-4.1 (t-like, 2H), 4.23      (d,      1H), 4.60 (d, 1H), 6.5-7.5 (m, 7H)       74 CH(CH.sub.3).sub.2      ##STR21##       White crystalsm.p. 102-104° C. 3140, 2970,1440, 1220 0.72 (d,      3H), 1.07 (d, 3H), 2.2-3.0 (m, 1H), 3.3-3.6 (brs, 1H), 4.23 (d, 1H),      4.56 (d, 1H), 5.01 (s, 2H), 6.4-7.5 (m, 11H)

Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein. 

What is claimed as new and desired to be secured by letters patent is:
 1. An imidazole derivative represented by the following formula (I): ##STR22## wherein R₁ represents an alkyl group, and R₂ represents a hydrogen atom or a nonheterocyclic aralkyl group which may have a substituent on the aryl moiety; or an acid adduct thereof.
 2. The imidazole derivative of claim 1, wherein R₁ is selected from the group consisting of methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, t-butyl, pentyl, hexyl, octyl, and cyclopropyl.
 3. The imidazole derivative of claim 1, wherein R₂ is selected from the group consisting of phenylalkyl and naphthylalkyl.
 4. The imidazole derivative of claim 1, wherein said substituent on the aryl moiety is selected from the group consisting of a halogen atom, a lower alkyl group, a lower alkoxy group, a lower alkanoyl group, and a cyano group. 